Optimization and application of influence function in abrasive jet polishing

We analyze the material removal mechanism of abrasive jet polishing (AJP) technology, based on the fluid impact dynamics theory. Combined with the computational fluid dynamics simulation and process experiments, influence functions at different impingement angles are obtained, which are not of a regular Gaussian shape and are unfit for the corrective figuring of optics. The influence function is then optimized to obtain an ideal Gaussian shape by rotating the oblique nozzle, and its stability is validated through a line scanning experiment. The fluctuation of the influence function can be controlled within +/- 5%. Based on this, we build a computed numerically controlled experimental system for AJP, and one flat BK7 optical glass with a diameter of 20 mm is polished. After two iterations of polishing, the peak-to-valley value decreases from 1.43 lambda. (lambda = 632.8 nm in this paper) to 0.294 lambda, and the rms value decreases from 0.195 lambda to 0.029 lambda. The roughness of this polished surface is within 2 nm. The experimental result indicates that the optimized influence function is suitable for precision optics figuring and polishing. (C) 2010 Optical Society of America